/*
 * Copyright (c) 2007 innoSysTec (R) GmbH, Germany. All rights reserved.
 * Original author: Edmund Wagner
 * Creation date: 30.05.2007
 *
 * Source: $HeadURL$
 * Last changed: $LastChangedDate$
 * 
 * the unrar licence applies to all junrar source and binary distributions 
 * you are not allowed to use this source to re-create the RAR compression algorithm
 * 
 * Here some html entities which can be used for escaping javadoc tags:
 * "&":  "&#038;" or "&amp;"
 * "<":  "&#060;" or "&lt;"
 * ">":  "&#062;" or "&gt;"
 * "@":  "&#064;" 
 */
package ir.mahdi.mzip.rar.io;

import java.io.EOFException;
import java.io.IOException;

public class ReadOnlyAccessByteArray implements IReadOnlyAccess {

    private int positionInFile;
    private byte[] file;

    public ReadOnlyAccessByteArray(byte[] file) {
        if (file == null) {
            throw new NullPointerException("file must not be null!!");
        }
        this.file = file;
        this.positionInFile = 0;
    }

    public long getPosition() throws IOException {
        return positionInFile;
    }

    public void setPosition(long pos) throws IOException {
        if (pos < file.length && pos >= 0) {
            this.positionInFile = (int) pos;
        } else {
            throw new EOFException();
        }
    }

    public int read() throws IOException {
        return file[positionInFile++];
    }

    public int read(byte[] buffer, int off, int count) throws IOException {
        int read = Math.min(count, file.length - positionInFile);
        System.arraycopy(file, positionInFile, buffer, off, read);
        positionInFile += read;
        return read;
    }

    public int readFully(byte[] buffer, int count) throws IOException {
        if (buffer == null) {
            throw new NullPointerException("buffer must not be null");
        }
        if (count == 0) {
            throw new IllegalArgumentException("cannot read 0 bytes ;-)");
        }
        int read = Math.min(count, file.length - positionInFile - 1);
        System.arraycopy(file, positionInFile, buffer, 0, read);
        positionInFile += read;
        return read;
    }

    public void close() throws IOException {
    }
}
